code: def test_lightgbm_checkpoint():
      preprocessor = DummyPreprocessor()
      checkpoint = LightGBMCheckpoint.from_model(
          booster=model, preprocessor=preprocessor
      )
      assert get_num_trees(checkpoint.get_model()) == get_num_trees(
          model
      )
      assert checkpoint.get_preprocessor() == preprocessor
  
file_path: ray/python/ray/train/tests/test_lightgbm_predictor.py
imports: import re
  import lightgbm
  import numpy
  import pandas
  import pytest
  from ray.air.constants import MAX_REPR_LENGTH
  from ray.air.util.data_batch_conversion import _convert_pandas_to_batch_type
  from ray.train.lightgbm import LightGBMCheckpoint, LightGBMPredictor
  from ray.train.predictor import TYPE_TO_ENUM
  from ray.train.tests.dummy_preprocessor import DummyPreprocessor
label_desc: Use image node_id 3 for calling a global function with example usage: test_lightgbm_checkpoint() without return types